c# memo

  Today,User found some bugs in my WIPThreeSites. It made me feel shy!
  Then i began to debug my System. Finally,i found three bugs in my programm.there bugs looked  were not worthy  of mention.

  (1) when the data reloaded,error takes place.
        The information from the dataBase was modified,and then would been reloaded,when the DataSource was binged to the dataGrid again ,The message said:some column can't been found,and then system was exited immediately.
        If make the dataSource null before reloading,this bug will be removed.
        This.dataGrid1.DataSource=null;
         This.dataGrid1.DataSource=dv;

  (2) AcceptChange( )
       In my programm,i use this sentence : ds.table[0].rows[0].delete( ); for deleting a row.
but when i saved the changed information ,i found that the row i had deleted was still existed.
      If you want to delete the row ,you should add a sentence below the delete();
         ds.table[0].row[i].delete():        
          ds.AcceptChanges();
  (3)Compare
       make a compare with a and b, if a==b,then do something;It looks so easy,but you will make a mistake if you are careless.In order to remove  space  ,you should do like this:
        if(a.Trim()==b.Trim())
        {  //  Do something   }